Wartime light carriers were conversions, not modular common hulls

How much can a common hull support different warship types, as with US light cruisers and light carriers in World War II?

Those ships were mainly cruiser hulls converted during construction, and large hulls are generally easier to rearrange than tightly packed small hulls.

The conversion worked because cruiser and carrier proportions could be close enough for a large unfinished hull to accept a radically different purpose. That opportunistic wartime adaptation differs from designing one modular hull for several missions from the outset. Space and displacement provide options; a smaller hull leaves far less room to move machinery, aviation facilities, protection, and stores.